Acapella Maker - Acapella Maker is an intelligent application that allows you to make the desired video collage in an automated and easy way.
UltraStar Deluxe - A free and open source karaoke game inspired by the Singstar™ game, runs on Windows, Linux and macOS.
PhotoGrid - Picsart removed a lot of grid options from its collage feature, and limited the amount of pictures to 10. While this app is inferior to Picsarts quality, it lets you choose max 15 pictures and has numerous layouts.
Yokee - Karaoke to YouTube videos
Midifun Karaoke - Midifun Karaoke created and published by Puasoft.
KaraFun - KaraFun is the best online karaoke. Over 35,000 karaoke songs, with studio quality, at home or on the go. Regular updates. Free demo!